*The vernier caliper is one of the most commonly used measuring instruments in the industry. Let me try & explain how it works.*

__Fig.1: The Vernier Caliper__

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*Least Count:*

*Simply put, the least count of a vernier caliper is the minimum measurement one can measure, using that vernier. All the measurements possible on a Vernier Caliper, are multiples of it's Least Count.*

*A Vernier with Least Count of 0.05mm (Fig.2) can measure from 0.05mm, and it's multiples, like 0.1mm, 1.15mm, 50.5mm etc.*

__Fig.2__

*A Vernier with Least Count of 0.02mm (Fig.3) can measure from 0.02mm, and it's multiples, like 0.12mm, 6.18mm, 45.5mm etc.*

__Fig.3__

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*Main Scale:*

*The Main Scale on a Vernier Caliper is the fixed scale (refer Fig.1). It's very important to know the value of a Main Scale Graduation. Figs.4 & 5 show one main scale graduation.*

__Fig.4__

__Fig.5__

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*Vernier Scale:*

*The Vernier Scale on a Vernier Caliper is the sliding scale (refer Fig.1). One Vernier Scale Graduation (Figs.6 & 7) is a fraction of One(or n) Main Scale Graduation (it is also equal to the difference between one(or n) Main Scale Graduation & the Least Count).*

__Example. 1__(refer Figs.4 & 6):*1 Main Scale Graduation(M) = 1mm*

*1 Vernier Scale Graduation(V) = 0.95mm*

*Least Count(LC) = 0.05mm*

*M - LC = VC*

__Fig.6__

__Example. 2__(refer Figs.5 & 7):*1 Main Scale Graduation(M) = 0.025 inches*

*1 Vernier Scale Graduation(V) = 0.049 inches*

*Least Count(LC) = 0.001 inches*

*2(*

*M*

*) - LC = VC*

__Fig.7__

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*Calculating Least Count:*

*The Least Count of a Vernier Caliper is not necessarily marked/written on every Vernier Caliper. The user should know how to find out the Least Count, which also helps in understanding the principal behind the Vernier Caliper.*

__Fig.8__

*Careful observations of Fig.8 reveals that 20 Vernier Scale Graduations(V) equal 19 Main Scale Graduations(M). Let's call the No. of Vernier Scale Graduations, n.*

*nV = (n-1)M*

*nV = nM - M*

*V = M - M/n*

*V = 1 - 1/20 (since M = 1 mm)*

*V = 1 - 0.05*

*V = 0.95 mm*

*Least Count(LC) = M - V*

*LC = 1 - 0.95*

*LC = 0.05 mm*

*The Least Count can also simply be calculated as:*

*LC = M/n*

*LC = 1/20*

*LC = 0.05 mm*

__Fig.9__

*The Least Count for the Vernier Caliper in Fig.9 (Inches) can simply be calculated as:*

*LC = M/n*

*LC = 0.025/25*

*LC = 0.001 Inches*

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*Working of the Vernier Caliper:*

*A movement equal to the Least Count or it's multiple, of the Vernier Scale, results in alignment of a Main Scale & a Vernier Scale graduation, which gives the measurement.*

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*Vernier Caliper Animated:*

*I've tried to show how the consecutive vernier scale graduations align with the consecutive main scale graduations, after each movement of the least count.*

*I hope this article was helpful. Let me know if you would like me to come up with an article on a topic which interests you.*

Comments and/or suggestions are most welcome.

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